I'm new to PyTorch and wrote a simple code as following to classify some inputs. The model input has 8*2 with batch size of 2 and the input layer in the model has 2 nodes. I don't know what is wrong!
X1=np.array([[2,1],[3,2],[-4,-1],[-1,-3],[2,-1],[3,-3],[-2,1],[-4,-2]])
Y1=np.array([0,0,0,0,1,1,1,1])
X=torch.tensor(X1)
Y=torch.tensor(Y1)
BATCH_SIZE=2
trainset= torch.utils.data.TensorDataset(X, Y)
trainloader = torch.utils.data.DataLoader(trainset, batch_size=BATCH_SIZE,
shuffle=True, num_workers=1)
from torch.nn.modules import flatten
learning_rate = 0.01
num_epochs = 20
device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu")
model = MyModel()
model = model.to(device)
criterion = nn.CrossEntropyLoss()
optimizer = torch.optim.Adam(model.parameters(), lr=learning_rate)
## compute accuracy
def get_accuracy(logit, target, batch_size):
''' Obtain accuracy for training round '''
corrects = (torch.max(logit, 1)[1].view(target.size()).data == target.data).sum()
accuracy = 100.0 * corrects/batch_size
return accuracy.item()
model = MyModel()
# Commented out IPython magic to ensure Python compatibility.
for epoch in range(num_epochs):
train_running_loss = 0.0
train_acc = 0.0
## training step
for inputs, labels in trainloader:
#inputs=torch.flatten(inputs)
inputs,labels=inputs.to(device), labels.to(device)
#inputs = inputs.to(device)
#labels = labels.to(device)
optimizer.zero_grad()
## forward + backprop + loss
print(inputs)
outputs = model.forward(inputs)
loss = criterion(outputs, labels)
loss.backward()
## update model params
optimizer.step()
train_running_loss += loss.detach().item()
train_acc += get_accuracy(outputs, labels, BATCH_SIZE)
#model.train()
model.eval()
print('Epoch: %d | Loss: %.4f | Train Accuracy: %.2f'%(epoch, train_running_loss / i, train_acc/i))
And my model is as below:
class MyModel(nn.Module):
def __init__(self):
super(MyModel, self).__init__()
self.d1 = nn.Linear(2,3)
self.d2 = nn.Linear(3,1)
self.init_weights()
def init_weights(self):
k1=torch.tensor([0.1,-0.72,0.94,-0.29,0.12,0.44])
k1=torch.unsqueeze(torch.unsqueeze(k1,0),0)
self.d1.weight.data=k1
k2=torch.tensor([1,-1.16,-0.26])
k2=torch.unsqueeze(torch.unsqueeze(k2,0),0)
self.d2.weight.data=k2
def forward(self, x):
x = self.d1(x)
x = F.tanh(x)
x = self.d2(x)
out = F.sigmoid(x)
return out
Then I got an error:
---------------------------------------------------------------------------
RuntimeError Traceback (most recent call last)
<ipython-input-27-196d819d3ccd> in <module>
101 print(inputs)
102
--> 103 outputs = model.forward(inputs)
104 loss = criterion(outputs, labels)
105
2 frames
/usr/local/lib/python3.8/dist-packages/torch/nn/modules/linear.py in forward(self, input)
112
113 def forward(self, input: Tensor) -> Tensor:
--> 114 return F.linear(input, self.weight, self.bias)
115
116 def extra_repr(self) -> str:
RuntimeError: t() expects a tensor with <= 2 dimensions, but self is 3D
I flatten the input but nothing changed. What should I do to fix it?
First of all, you don't need to invoke your model's forward pass by model.forward(x); using model(x) is good.
Second of all, what exactly are you trying to achieve via the init_weights method? You're unsqueezing k1 and k2 twice, giving them the shape of (1, 1, x) which is 3D which is what the error is telling you. torch.nn.Linear performs a matrix multiplication with a 2D matrix, so you can't use a 3D one. torch.nn.Linear already initializes the weights via Kaiming initialization [1] so I'm not sure what you're trying to achieve here.
Changing the init_weights method to:
def init_weights(self):
k1 = torch.tensor([0.1, -0.72, 0.94, -0.29, 0.12, 0.44])
k1 = k1.reshape(self.d1.weight.shape)
self.d1.weight.data = k1
k2 = torch.tensor([1, -1.16, -0.26])
k2 = k2.reshape(self.d2.weight.shape)
self.d2.weight.data = k2
and changing the type of inputs from Long to Float (i.e., model(inputs.float())) should solve your problem.
References
[1] https://github.com/pytorch/pytorch/blob/0dceaf07cd1236859953b6f85a61dc4411d10f87/torch/nn/modules/linear.py#L103